Are built-in AI memory features actually useful or do they mess things up?

I tried relying on the auto memory features built into most chat tools to remember my project preferences but half the time it saves random details I don't care about and forgets the stuff that actually matters. Then it starts bringing up outdated context from three weeks ago into a brand new conversation which is super annoying.

Do you turn those built in memory features off and start fresh every time or have you found a way to make them work reliably?